1. Field of the Invention
The present invention relates to a window-mounted type air conditioner, and more particularly, to an air-circulation fan arrangement of such an air conditioner.
2. Prior Art
A window-mounted type air conditioner has an outdoor heat exchanger (called a condenser) which is installed at the outer side of a window and used in condensing a compressed refrigerant, and an indoor heat exchanger (called an evaporator) which is installed at the inner side of the window and used in evaporating a refrigerant condensed in the outdoor heat exchanger so as to absorb heat of ambient room air.
The appearance of the body of such a window-mounted type air conditioner is formed by a front cover, rear cabinet, and a base.
The front cover has a suction grill through which room air is drawn into the air conditioner, and a discharge grill for discharging cool air.
The indoor heat exchanger and the outdoor heat exchanger are disposed on a base and are spaced from each other at a predetermined distance. Between the indoor heat exchanger and the outdoor heat exchanger is disposed a duct having a passage for air flow. The duct 60 has, as shown in FIG. 1, guides 61a and 62a for forming a scroll type air passage. The reference numeral 71 shown in the figures is a cross-flow fan (hereinbelow, referred to as a `first fan`). The first fan 71 is assembled to a shaft 70a of a fan motor disposed on an appropriate position in the duct 60. As the first fan 71 rotates, outside air which is in the room is drawn into the first fan 71 along the axis thereof, and then discharged along the outer circumference thereof. The discharged air is guided by the air passage of the duct 60 so as to be discharged into the room through the discharge grill of the front cover. In such a situation, the discharged air is cool air which has been cooled while it passes through the indoor heat exchanger.
Meanwhile, at the opposite side of the fan motor is installed a second fan facing the outdoor heat exchanger. Furthermore, on a side of the base, a compressor is mounted for compressing the refrigerant into a refrigerant of high temperature and pressure.
The refrigerant which has passed through the indoor heat exchanger is compressed by the compressor to a high temperature and pressure, and the compressed refrigerant exchanges heat with the ambient air of room temperature in the outdoor heat exchanger. The liquid refrigerant of room temperature and high pressure which has undergone such a heat exchange process is reduced in pressure by a capillary tube, and then flows into the indoor heat exchanger.
Meanwhile, the air in the room which is drawn through the suction grill by the first fan 71 flows into the indoor heat exchanger. The drawn air is cooled while it passes through the indoor heat exchanger. The cooled air flows along the air passage of the duct 60 by the first fan 71 and then is discharged into the room thereby through the discharge grill.
However, in the general window-mounted type air conditioner having such a construction, the sectional area A1 of a part 60a of the air passage formed by the duct 60 is broad, while the sectional area A2 of another part 60b of the air passage (located upstream of the part 60a) formed by the duct 60 is narrow.
Therefore, when the first fan 71 rotates to draw and discharge the outside air, a lot of air traverses the broad air passage, but a small amount of air traverses the narrow air passage since the pressure of air therein is low. Even worse, some of the air being discharged from the area A1 reenters the narrow air passage as shown at R in FIG. 2. This is because the velocity of the air flowing through the passage having broad sectional area A1 is low, while the velocity of the air flowing through the passage having narrow sectional area A2 is relatively high. Thus, a part of the slow air is inhaled into the passage of the fast air.
Such an inverse flow of the air causes a noises, a lowering of the cooling capacity versus size, and increase of the power consumption, so an improvement thereon is desired.